/**
 * Serene (simple) - A PoC lisp to collect data on Serenes concepts
 * Copyright (C) 2019-2020 Sameer Rahmani <lxsameer@gnu.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 */
package serene.simple;

import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.Console;
import java.io.FileInputStream;


public class Main {
  private static String licenseHeader = "\nSerene(simple), Copyright (C) 2019-2020" +
    "Sameer Rahmani <lxsameer@gnu.org>\n" +
    "Serene(simple) comes with ABSOLUTELY NO WARRANTY;\n" +
    "This is free software, and you are welcome\n" +
    "to redistribute it under certain conditions; \n" +
    "for details take a look at the LICENSE file.\n";

  private static void isJava8() throws RuntimeException {
    if (System.getProperty("java.vm.specification.version").equals("1.8"))
      throw new RuntimeException("Minimume required version of JDK is 1.8");
  }

  public static void main(String[] args) throws IOException, RuntimeException {
    Main.isJava8();

    if (args.length == 0) {
      startRepl();
      return;
    }
    runSerene(args[0]);
  }

  private static void startRepl() throws IOException {
    BaseScope rootScope = new RootScope();

    Console console = System.console();

    System.out.println("Serene 'simple' v0.1.0");
    System.out.println(licenseHeader);

    while(true) {
      String inputData = console.readLine("serene-> ");
      //String inputData = "(fn (x) x)";

      if (inputData == null) break;

      ByteArrayInputStream inputStream = new ByteArrayInputStream(inputData.getBytes());


      try {
        ListNode<Node> nodes = Reader.read(inputStream);
        Object result = ListNode.EMPTY;

        for (Node n : nodes) {
          result = n.eval(rootScope);
        }

        if (result != ListNode.EMPTY) {
          System.out.print(";; ");
          if (result == null) {
            System.out.println("nil");
          }
          else {
            System.out.println(result.toString());
          }
        }
      }
      catch(Exception e) {
        System.out.println("Error: ");
        e.printStackTrace(System.out);
      }

    }
  }

  private static void runSerene(String filePath) throws IOException {
    BaseScope rootScope = new RootScope();

    ListNode<Node> nodes = Reader.read(new FileInputStream(filePath));

    for (Node n : nodes) {
      n.eval(rootScope);
    }
  }
}